1. Field of the Invention
Embodiments of the present disclosure relate to display technology, and more particularly to a liquid crystal display and the backlight module thereof.
2. Discussion of the Related Art
Coupling efficiency, which relates to the light efficiency emitted from LEDs to a light guiding plate, is the most important factor affecting the brightness of edge-in backlight modules. The coupling efficiency depends on a coupling distance, which indicates the distance between light emitting surfaces of the LEDs and the light incident surfaces of the light guiding plates.
FIG. 1 is a cross-sectional view of a typical edge-in backlight module. The “d” indicates the coupling distance between a LED 10 and a light guiding plate 11. FIG. 2 is a line diagram showing a relationship between the coupling effect and the coupling distance when the thickness of the light guiding plate is equal to 2 mm. As shown in FIG. 2, the coupling effect reduces from 87 percents to 80 percents when the coupling distance is increased from 0.1 mm to 0.8 mm. At the same time, the brightness of the backlight module is reduced from 300 nits to 276 nits.
However, the coupling distance may be slightly different from a desired value due to parameters of mechanical components, assembly deviations, and so on. Such differences may result in a larger coupling distance and the brightness of the backlight module is affected.